Nazi Germany (1944)
Parasite Interceptor – None Built 

The Sombold So 344 was a highly specialized interceptor designed by Heinz G. Sombold to attack Allied bomber formations over Germany in 1944. The way the aircraft would attack, however, would be extremely unconventional. Being deployed from a bomber mothership, the So 344 would fly towards an approaching bomber formation and launch its entire nose cone, which was a 400 kg (882 Ib) rocket, at the enemy bombers in an attempt to destroy as many as possible. From there, the So 344 could either attack the remaining bombers or return to base and land on a skid. Work went as far as wind tunnel models for the aircraft but none would be built.

History

Towards the end of the Second World War, Germany found itself at odds on an almost daily basis against the threat of Allied bombers. While pre-existing aircraft were used to defend Germany from this threat, more and more proposals for aircraft designed to deal with enemy bombers began to emerge. A number of these projects would use extremely unorthodox or downright strange methods to attempt to destroy enemy bombers. These ranged from carrying specialized weapons to even ramming the bomber. These projects were often small in design and were made of widely available materials, like wood, to save on production costs, reserving the more important material for mainline aircraft. An aircraft produced in small numbers that followed this formula was the Bachem Ba 349 “Natter”. Although not used operationally, the Ba 349 was a small bomber interceptor that would not require an airstrip to take off. Instead, it would be launched vertically from a launch rail. After taking off, the Ba 349 would approach the Allied bombers and attack them with a salvo of rockets in the nose. With its ammo depleted, the pilot would then eject from the aircraft, with the aircraft’s engine section parachuting down and being recovered for reuse. The nose would break off for the pilot to deploy the rockets under the cone. The Ba 349 is the most well known of these projects, but many would never leave the drawing board. Many of these aircraft designs were created by large companies but a handful came from individual engineers. One such design, the Sombold So 344, would approach the destruction of enemy bombers in an entirely different, almost ludicrous way.

The Sombold So 344 was the idea of Heinz G. Sombold of the Bley Ingenieurbüro (Engineering Office). Bley Segelflugzeug was a sailplane manufacturer located in Naumburg, Germany. During the 1930s, they became popular for their various sailplane designs, like the Kormoran and Motor-Kondor designs. Heinz G. Sombold was an engineer at Bley. He began working on the So 344 in late 1943 and his aircraft incorporated many features of the sailplanes built by the company. At the time, the craft was only designed as a parasite escort fighter and armed with two machine guns. On January 22nd of 1944 however, Sombold would drastically change the design and purpose of the aircraft. From here, the aircraft would be designed for the destruction of enemy bombers. To fit this new role, it would use a very unorthodox weapon. The nosecone of the So 344 was a rocket filled with 400 kg (880 Ib) of explosives that could be launched by the pilot at enemy aircraft. Sombold envisioned his aircraft using its nosecone rocket against close formations of bombers, where multiple aircraft could be destroyed with one well placed explosive. American bombers would often fly in combat box formations, where the bombers would fly close together to maximize the defensive capabilities of their guns. This allowed the bombers to have ample protection from enemy interceptors, as the approaching craft would come under fire from most of the aircraft in said formation. There were earlier weapons deployed by the Germans to try and damage the closely packed formations, like the BR 21, but none would be as huge a payload as the Sombold’s nose rocket.

Design work on the So 344 continued through 1944, even going as far as having a ⅕ scale wind tunnel model being made and tested at the Bley facility. By 1945, work on the project was cut off, as the Bley facility had to be abandoned due to the encroaching warfront. No further work was done on the Sombold So 344 and Sombold’s fate is unknown. No other designs by Sombold are known to have existed. The 344 designation was later used for the Ruhrstahl X-4, or RK 344, air-to-air missile system.

A photo has circulated in several books, as well online, that claims a nosecone of the So 344 was built and discovered by the Allies at the end of the war. However, this photo actually depicts the nose section of a Wasserfall surface-to-air missile. The nose of the Wasserfall easily could be confused for that of the Sombold’s, as its shape is semi-similar and both have four stabilizing fins. No So 344 was built.

Design

The Sombold So 344 was a single man special attack aircraft. It was to have a short, tubular body of wooden construction. For ease of transport, the aircraft could be split into two sections. The cockpit would be located at the rear of the body, directly in front of the vertical stabilizer. The aircraft would have conventional control surfaces on its wings and stabilizers. At the ends of the horizontal stabilizers were two angled vertical stabilizers. The wings would be mid-set. For its powerplant, the So 344 would use a Walter 509 bi-fuel rocket engine. To conserve fuel, the aircraft would be deployed via bomber mothership. Once deployed, it would have around 25 minutes of fuel. To land, the So 344 would have a rounded ski built into the body, similar to how the sailplanes Bley created would land.

For its main armament, the So 344 had a massive unguided rocket as its nose cone. The nose would contain 880 Ibs (400 kg) of explosive Acetol. The rocket was triggered via a proximity fuse. For stabilization, four fins would be placed on the nose. Additionally, the So 344 would have two forward machineguns to either defend itself or attack other bombers once its payload was released.

Operations

The So 344 would be carried to an approaching bomber formation via a modified bomber mothership. Once deployed, the aircraft would move in an arc towards the bombers, coming in downwards at them from at least 3,300 ft (1,000 m) above. This height would protect the So 344 from defensive fire during its dive. When the aircraft was lined up with a group of bombers, the pilot would launch the nosecone into the middle of the formation. Given the close proximity of the bombers in formation and the explosive threshold of the nosecone, it was predicted the resulting explosion would be able to take down several bombers in one attack. After launching its nosecone, the So 344 would have some fuel left and could continue to attack the remaining bombers with two machine guns on the aircraft. When fuel was low, the aircraft would return to base via gliding, like the Messerschmitt Me 163B rocket interceptor. Once near an airfield, it used a large ski to land.

Conclusion

The So 344 was a very strange way of approaching the bomber problem over Germany late in the war. The logic behind it was not too far fetched. The aforementioned Ba 349 Natter followed a similar attack plan, approaching the bombers and firing off a salvo of rockets before the pilot bailed from the craft. A project like the So 344 was not new to Germany by that point in the war and, like most of its contemporary designs, was not produced.

Had it been produced, the So 344 would have been a very niche aircraft. The fact that the aircraft had a single shot from its rocket payload made accuracy extremely important. The aircraft also would have been a prime target for Allied escort fighters once it ran out of fuel. A bomber would also need to be modified to carry the So 344 and would be a prime target for the escort fighters once the attacker was launched. The nature of the aircraft has led it to wrongly be named a “suicide attacker” by many postwar books on the subject. In some instances, the craft is also incorrectly listed as being a ramming aircraft. It is likely the aircraft would not have impacted the war very much.

Variants

• Sombold So 344 (1943)– Original planned fighter version. Armed with two machine guns or heavier armament. None were built
• Sombold So 344 (1944)– The Sombold So 344 attack aircraft. Armed with a nosecone rocket which would be fired at enemy bomber formations. None were built.

Operators

• Nazi Germany – The Sombold So 344 was designed for the Luftwaffe to use against Allied bombers over Germany. None of the type would be built.

Sombold So 344 Specifications
Wingspan	18 ft 8 in / 5.7 m
Length	22 ft 11 in / 7 m
Height	7 ft 1 in / 2.2 m
Wing Area	64.58 ft² / 6 m²
Engine	Walter 509 Bifuel rocket engine
Weight	2,976 Ib / 1,350 kg
Flight Time	25 minutes
Crew	1 pilot
Armament	2x machine guns  1x 880 Ib (400 kg) Nose Rocket

Gallery

Video

Credits

• Article by Marko P.
• Edited by Henry H. and Stan L.
• Illustration by Ed Jackson
• Herwig, D. & Rode, H. (2003). Luftwaffe Secret Projects: Ground Attack & Special Purpose Aircraft. Hinckley, England: Midland Pub.
• http://www.luft46.com/misc/so344.html